Eurosceptics have been branded "terrorists" just days before Tony Blair prepares to fly to Brussels to smuggle in the new EU constitution by the back door.

Critics of the EU’s secret plans to bring back the failed European constitution by stealth at this week’s summit were blasted by the Italian President, Giorgio Napolitano.

The Italian head of state told a news conference in Siena last week that "those who are anti EU are terrorists".

And he attacked eurosceptics who warn that the promised new EU treaty will go too far in eroding the powers of member states, saying: "It is psychological terrorism to suggest the spectre of a European superstate."

His comments emerged as EU foreign ministers gather in Luxembourg today to negotiate the new treaty to replace the failed EU constitution, ahead of a summit of EU leaders in Brussels on Thursday.

Ahead of what will be his last major political event before he hands over to Gordon Brown, Mr Blair has been forced to deny widespread claims that he will seek to sign up to a new treaty which will revive the key planks of the constitution, which was doomed after it was rejected by French and Dutch voters in referendums in 2005.

It is psychological terrorism for critics of the EU to suggest the spectre of a European superstate

Giorgio Napolitano

Downing Street issued a list of Britain’s "red line" issues where Mr Blair will refuse to hand over powers to Brussels, such as the veto on criminal justice and labour law and Britain’s seat on the UN security council, but refused to offer British voters a referendum on the treaty.

But critics say Mr Blair is, like most other EU leaders, determined to bring the failed EU constitution in by the back door by simply renaming the document as an "amending treaty" and slimming down its original 500 pages.

Campaigners for national referendums on the proposed treaty were left outraged when President Napolitano spoke out last Monday alongside the German President, Horst Kohler, who nodded in agreement at his comments.

President Kohler also described the tactics of eurosceptics as "populistic, demagogic campaigning".

The words of the two men were seen by many in their home countries as a thinly veiled attempt to link euroscepticism with the demagoguery and populism of the fascist regimes of Adolf Hitler and Benito Mussolini.

Mr Blair’s claim that the new treaty is not simply a re-hash of the rejected constitution were dismissed by eurosceptic campaigners, who pointed to the statements of other European politicians in recent weeks.

German Chancellor Angela Merkel, in a letter to fellow leaders, revealed last wek that most countries want to keep the "substance" of the constitution.

And former French president Valéry Giscard d’Estaing, a key architect of the EU constitution, said last week: "I am strongly opposed to a mutilated treaty. The European Council must establish a clear road map and a clear mandate to achieve the process for the ratification of the constitutional treaty."

Meanwhile, German Foreign Minister Frank-Walter Steinmeier recently said "closed-door negotiations among the 27 EU governments were making progress in deciding on what to do with the constitution", adding: "Everyone wants to push this forward."

UKIP leader, Nigel Farage MEP, said: "This treaty is the constitution by another name. The agenda has always been to sneak it in under another guise. It is a deliberate and deceitful attempt to prevent free and fair referendums not just in Britain but all European countries.

"It will have enormous adverse implications for Britain, yet it is just being bulldozed through. Blair will sign away our future - just days before he leaves No 10 - and his legacy will be a hand grenade with the pin pulled out."